Cleaner burning fuels are desired to reduce the impact of fossil fuel combustion on the Earth's environment. One approach reducing the impact of combustion is using hydrogen as a fuel. When hydrogen is burned, the resulting product of combustion is water.
Hydrogen can be used as the fuel in internal combustion engines. For example, Air Products and Chemicals, Inc. operates a hydrogen-powered Ford E-450 shuttle bus on the Trexlertown, Pa. campus.
Another option is to burn compressed natural gas (CNG). And yet another option is to burn a mixture of hydrogen and compressed natural gas (HCNG). The town of Hempstead, N.Y. has a project to demonstrate the generation of hydrogen and a blend of hydrogen and natural gas, and the use of these fuels in motor vehicles (http://www.tohcleanenergyproject.org).
Industry desires to blend compressed gases from multiple sources, the blends having specified compositions.
Industry desires to provide accurate blending of compressed gases where the resulting composition of the compressed gas blend is tolerant of variations in the supply pressures of the compressed gas sources, and tolerant of variations of system pressures during delivery of the compressed gases.